CX25870/871
Appendix D Closed Caption Pseudo Code
Flicker-Free Video Encoder with Ultrascale Technology
fxn //this should
already exist //some-
where in customer’s
code
Write CCR_START(CCR_START_hex);
//CCR_START[8:0] reg-
ister is
//comprised of bit[4]
of regis-
ter
//0xD4 and bits[7:0]
of
CX870/871
//register 0xD0
}
{
else
// 625-line format = PAL is being transmitted by
CX870/871
//this assumes PAL-M with its’ 525 line format is
not allowed
[equation] CC_ADD = ($pow(2,
CBITS+5)/1716)*1728.0/H_CLKO;
//eqn to determine CC_ADD
register for PAL
CC_ADD_hex =
DEC_TO_HEX_CONVERSION(float CC_ADD);
//assumes DEC_TO_HEX_CONVERSION fxn
//this should already exist //some-
where in customer’s code
Write CC_ADD(CC_ADD_hex);
//CC_ADD[11:0] register is
//comprised of
bits[3:0] of
//register 0xD4
and bits[7:0] of
//CX870/871 reg-
ister 0xD2
[equation] CCR_START =
H_CLKO*10.003*27/1728 + CC_PIPE1;
//eqn to determine CCR_START reg-
ister for PAL
CCR_START_hex = DEC_TO_HEX_CONVERSION(float
CCR_START);
//assumes DEC_TO_HEX_CONVERSION fxn
//already exists somewhere in //cus-
tomer’s code
100381B
Conexant
D-3
CONEXANT [ CONEXANT SYSTEMS, INC ]
